A project has been undertaken by MCLB to have Retro-Commissioning performed that includes: review of building systems existing conditions; development of listing of repairs and modifications to operations; and then field work to complete the changes. The project included four of the bases buildings that varied greatly in age, normal occupancy of use, and operating system types. The results of the surveys resulted in changes that were sometimes immediate in application and others where replacement of parts and alterations of operations strategies will have long term benefits in energy reductions.